Ratories



Sept. 28, 1926. 1,600,980

w. H. GE'RNS ELECTROMAGNETIC SOUND REPRODUCER Filed Dec. 11. 1925 3 JE- l 5 a 8 l i B Y 6 0 TTORNEY for UNITED. STATES 1,600,980 PATENT OFFICE.

WILLIAM H. eE Ns, 0E EAs'r ORANGE; NEW JERSEY, AssrGNon T0 BRANnEsLABo- RATORIES, 11510., 01? NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

I :ELECTROMAGNETIC S OUND RE?RODUCER.

Application filed. December 11', 1925. Serial No. 74,802.

My invention relates broadly to electromagnetic sound reproducers and more particularly to a construction of loud speaker for use in radio reproduction.

On'e'of the objects of my invention is to provide a construction of loudspeaker radio Still another object of my invention is to provide a construction of loud speaker in which a single casting is provided with oppositely extending cylindrical portions, one of which serves as a support. for a sound amplifying horn'and the other of which serves as a support for an electromagnetic driving apparatus actuating a diaphragm positioned intermediate the extended cylindrical portions 'A" further object of my invention is to provide a single casting for supporting a sound amplifying horn and an electr'omag netic driving apparatuswith means for ad justa-bly positioning H the electromagnetic driving apparatus'with respect to a sound reproducing diaphragm for selecting the magnetic gap between the sound reproducing diaphragm and the electromagnetic driving apparatus for the desired tone quality of the reproduced sound; r

A still further object of my invention is to provide a loud speaker construction with an adjustable electromagnetic driver therein with means operative from the exterior ofthe loud speaker and rotatable in engagement with the support for the electromagnetic driver for adjusting the magnetic gap between the electromagnetic driver and a sound reproducing diaphragm with 'means for limitingthe movement of the electromagnetic driver in the direction of the sound reproducing diaphragm.

Still other objects of my invention relate to' 'the construction and assembly of aloud speaker mechanism in which a single casting is arranged Withga lateral apertured partition between 'oppositelyextending cllindrical portions which serve. to support a sound amplifying horn and an'electromagnetic driving mechanism Qrespectively, with means screw threaded into the cylindrical portion of the casting which houses the elec tro-magnetic driver for supportinga $011111 reproducing diaphragm with respect to which the electromagnetic driveris readily adjustable for varying tliemagnetic gap be tween the diaphragm; andthe electromagnetic driven, p v

, Other and furher objects of my invention will appear hereinafter as the following specification progresses and will be understoodflby. reference to the accompanying drawings, in which: I

Figure. 1 is a side elevation. partially broken away and illustrated in cross-section showing the. assembly of parts of the electromagnetic. sound reproducer. construction of my invention; and Fig. 2 is a plan-view lookingbeneath thebase of the'loud-speaker construction. V I

Referring to the drawings infdetail reference character 1 represents'the-single casting which supports all of the parts of the loud speaker.construction. iThe easting 1 has anupwardly extending cylindricalpor 1011 2 and a downwardly depending cylindrical portion 3 with an intermediate partition separating thecylindrical'portions as represented at 4. The partition a is aper tured at 5 for thedeliveryiof soundvibrationsto a sound amplifyinghorn supported in the cylindrical portion 2. Thecasting 1 is provided with an annular depending flange 6 immediately below the cylindrical portion 2 which flange cooperates with a corresponding flange 10 upon ascrew threaded ring member? to support thesound reprodu'cing. diaphragm 9.. The depending cylindrical portion 3 is interiorly screw threaded to receive the. ring member-7 and to receive thescrew threaded supporting: plate 12 which carries theelectromagnetic driver. The .screw threaded supporting plate 12is provided with an upwardly extending screw threaded wall 11 which engageswith the interior screw threads on the cylindrical portionB. Arubber ring member 8 circular in cross'gsectionis interposed between the upper extremityof the supportingplate and the lower face of; the screw threaded ring member 7 forming a cushion against which the supporting plate 12 may be adjusted to vary the size of, the magnetic gap between the electromagnets 15 and, the. diaphragm 9. The electromagnetic driver comprises a pair of electron'iagnets shown in elevation at 15 and the permanent magnet system 16. A central screw member 18 is provided in the supporting plate 12 from which an angu larly adjustable lever 19 projects. The lever 19 depends downwardly at 17 and is directed radially and then upwardly as represented at 20 being prevented from completing a 360 movement by abutment with the downwardly depending shaft member 21. The shaft member 21 is. journaled in the casting 1 as represented'at 22 and may be 10- tated under control of hand knob 23; A pinion 2% is carried on the lower extremity of the shaft member 21 and meshes with the teeth 1 1 formed on the peripheral edge of the supporting plate 12. v

The lever 19 forms a limiting stop against the movement of the electroinagnets 15 in the direction of diaphragm 9. The adjust ing screw 23 is prevented from revolving to a position where the electromagnets 15 abut against the surface of the diaphragm 9 by virtue of a selected setting of the stop lever 19 which prevents the upward travel of the electromagnets 15 beyond a predetermined and extremely small magnetic leakagegap. Rotation of the adjusting'knob 23 in an op posite direction to its final upward limit direction serves to retract the electromagnets 15 from the diaphragm 9 thereby enlarging themagnetic leakage gap. This process res sults in' deformation of. the resilient ring member 8, at all times establishing a ten sioned position of ring member and supporting plate 12 in the threads of the'depending cylindrical portion 3. The rapid vibrations to which the electromagnetic driving mechanism is subjected requires that allparts be assembled in such manner that thetendency to chatter'is eliminated and I find that'the construction of my invent-ion accomplishes this purpose.

In theassembly of the loud spaker, the base member 1 is inverted and the diaphragmfi seated on the annular flange 6. The ring member; 7 isscrewthreaded into the cylindrical portion 3 gripping the lower surface of diaphragm 9 by means of annular flange 10, Thetleforlnable gaskets is next p aced in positionand' the electromagnetic driver is then screwed into place, The screw member 18 is loosened to enable the top lever 19 to be screwed' in position at which movement of the electromagnets 15 is prevented beyond a desired limit, after which the desired adjustment may be obtained by a retractin movement of thesupporting plate 12 substantially through 360.

The construction of my invention described herein has been found to be extreme- 1y practical in quantity production and efficient. in its electrical operation. lVhile I have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon the invention are intended other than those imposed by the scope of the appended claims.

hat I claim and desire to secure by Letters Patent of the United States is as follows 1 i v V 1. An electromagnetic sound reproducer comprising in combination a base, a pair of cylindrical portions cast integral with said base, one of said portions xtending vertically and serving as a support for a sound amplifying horn -and the other of said portions depending downwardly and arranged to receive an adjustable electromagnetic driving apparatus therein, an apertured partition member separating said portions, a soundreproducing diaphragm supported below said partition member and adapted to be actuate-d lly said electromagnetic driving apparatus, a rotatable actuator extending upwardly through said base and operative from the exterior thereof, a pinion on said actuator arranged to engage with teeth positioned around the periphery of said electromagnetic driving apparatus for adjusting the magnetic gap between said electromagnetic driving apparatus and said sound reproducing diaphragm.

2. An electromagnetic, sound reproducer comprising in combination a base member, having a pair of cylindrical portions cast integral therewith, with one ofsaid ,portions extending upwardly and serving as a support for asound amplifying horn and the other of said portions depending downwardly and serving to receive a rotatable plate member carrying an electromagnetic driving apparatus thereon, a soundr'eproducing diaphragm carried in the upper extremity of said last mentioned cylindrical portion, a rotatable actuator journaled in said base member and operative from the exterior thereof, a pinion carried by said rotatable actuator and arranged to mesh with teeth formed on the peripheral edge of said rotatable plate member for advancing or retracting said electromagnetic driving apparatus with respect to said sound reproducing diaphragm for varying the magnetic gap therebetween.

3. An electromagnetic sound reproducer comprising in combination a base member having a pair of cylindrical portions cast integral therewith, with one of said portions extending upwardly and serving as a support for a sound amplifying horn and the other of said portions depending downwardly and serving to receive a rotatable at right angles to the plane of said r0 I tatable plate member, a pinion carried by said rotatable actuator and arranged to mesh with teeth formed on the peripheral edge of said rotatable plate member, a screw device centrally positioned in said rotatable plate member and having a radially extending lever secured thereon, said lever projecting beyond said rotatable actuator and arranged to abut with the downwardly depending end of said actuator forming a limit stop to prevent the movement of said electromagnetic driving apparatus beyond a predetermined magnetic gap with respect to said sound amplifying diaphragm, while permitting the adjustment of said magnetic gap to a largerpredetermined size upon rotation of said rotatable actuator.

4. An electromagnetic sound reproducer comprising'in combination a base member,

a support for .a sound reproducing dia-' phragm carried by said base member, an electromagnetic driving apparatus, a rotatable plate member for supporting said electromagnetic driving apparatus, said rotatable plate member being screw threaded into said base member to enable said electromagnetic driving apparatus to be advanced orr retracted from said sound reproducing diaphragm, a rotatable actuator extending through said base member and having a pinion thereon arranged to mesh with teeth formed on the'peripheral edge of said rotatable plate member, a radial lever centrally secured to said rotatable plate member and angularly adjustable about said plate member, said lever projecting beyond-said rotatable actuator and forming an abutment therewith, whereby said lever may be adjusted to .a particular angular position in abutment with said actuator for limiting the movement of said electromagnetic driving apparatus in the direction of said sound reproducing diaphragm, while permitting the enlargement of the magnetic gap between said sound reproducing diaphragm and said electromagnetic driving apparatus through a distance substantially equal to 360 rotation of said rotatable plate member.

WILLIAM H. GERNSQ 

